import java.util.HashSet;
import java.util.*;

public class Test {
    //只出现一次的数字
   /* class Solution {
        public int singleNumber(int[] nums) {
            HashSet<Integer> set = new HashSet<>();
            for (int x : nums) {
                if (! set.contains(x)) {
                    set.add(x);
                }else{
                    set.remove(x);
                }
            }
            for(int x : nums){
                if (set.contains(x)){
                    return x;
                }
            }
            return -1;
        }
    }*/
   /* class Solution {
        public int numJewelsInStones(String jewels, String stones) {
            HashSet <Character> set = new HashSet<>();
            int x = 0;
            for (char a : jewels.toCharArray()) {
                set.add(a);
            }
            for (char a : stones.toCharArray()) {
                if (set.contains(a)) {
                    x++;
                }
            }
            return x;
        }
    }*/
    //旧键盘
   /* public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            String a = in.nextLine();
            String b = in.nextLine();
            find(a,b);
        }
    }

    private static void find(String a, String b) {
        HashSet<Character> set = new HashSet<>();
        HashSet<Character> set1 = new HashSet<>();
        for (char ch : b.toUpperCase().toCharArray()) {
            set.add(ch);
        }
        for (char ch : a.toUpperCase().toCharArray()) {
            if (!set.contains(ch) && !set1.contains(ch)){
                System.out.print(ch);
                set1.add(ch);
            }
        }
    }*/
}
